Ebola in the air? A nightmare that could happen

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Photos:The Ebola epidemic

An Ebola survivor participates in a study in Monrovia, Liberia, on June 17. The country launched a five-year study to unravel the mystery of the long-term health effects that plague survivors of the viral disease. Since the epidemic started more than a year ago in a remote village in Guinea, more than 11,000 people have died, the vast majority in three West African nations, according to the latest numbers from the World Health Organization. And that number is believed to be low, since there was widespread under-reporting of cases, according to WHO.

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Photos:The Ebola epidemic

Women in Monrovia celebrate after the World Health Organization declared Liberia Ebola-free on May 9. Other cases have recurred since, however. Two people in Liberia have died of the disease since the end of June, just weeks after the WHO declared the nation free of the disease.

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Photos:The Ebola epidemic

A man walks past an Ebola awareness painting in Monrovia on March 22.

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Soldiers from the U.S. Army's 101st Airborne Division walk across the tarmac at Campbell Army Airfield before reuniting with their families at a homecoming ceremony March 21 in Fort Campbell, Kentucky. The 162 soldiers were deployed in Liberia, where they helped fight the spread of Ebola.

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Relatives weep for a loved one who it was believed died from Ebola, at a graveyard on the outskirts of Monrovia on March 11.

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Photos:The Ebola epidemic

Doctors Without Borders staffer Alex Eilert Paulsen watches as mattresses and bed frames burn at the Ebola Treatment Unit in Paynesville, Liberia, on January 31. The organization reduced its number of beds from 250 to 30 as gains were made in battling the virus.

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Pauline Cafferkey, a Scottish woman diagnosed with Ebola, is put on a plane in Glasgow, Scotland, on December 30, 2014. Cafferkey, a 39-year-old nurse who volunteered in Sierra Leone, was being transported to London for treatment.

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A child who survived the Ebola virus is fed by another survivor at a treatment center on the outskirts of Freetown, Sierra Leone, on November 11, 2014.

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Health workers in Monrovia cover the body of a man suspected of dying from the Ebola virus on October 31, 2014.

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Photos:The Ebola epidemic

Kaci Hickox leaves her home in Fort Kent, Maine, to take a bike ride with her boyfriend on October 30, 2014. Hickox, a nurse, recently returned to the United States from West Africa, where she treated Ebola victims. State authorities wanted her to avoid public places for 21 days -- the virus' incubation period. But Hickox, who twice tested negative for Ebola, said she would defy efforts to keep her quarantined at home.

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Health officials in Nairobi, Kenya, prepare to screen passengers arriving at the Jomo Kenyatta International Airport on October 28, 2014.

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Photos:The Ebola epidemic

U.S. President Barack Obama hugs Ebola survivor Nina Pham in the Oval Office of the White House on October 24, 2014. Pham, one of two Dallas nurses diagnosed with the virus, was declared Ebola-free after being treated at a hospital in Bethesda, Maryland. The other nurse, Amber Vinson (not pictured), was treated in Atlanta and also declared Ebola-free.

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Health workers in Port Loko, Sierra Leone, transport the body of a person who is suspected to have died of Ebola on October 21, 2014.

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Health workers bury a body on the outskirts of Monrovia on October 20, 2014.

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Photos:The Ebola epidemic

Garteh Korkoryah, center, is comforted during a memorial service for her son, Thomas Eric Duncan, on October 18, 2014, in Salisbury, North Carolina. Duncan, a 42-year-old Liberian citizen, died October 8 in a Dallas hospital. He was in the country to visit his son and his son's mother, and he was the first person in the United States to be diagnosed with Ebola.

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Boys run from blowing dust as a U.S. military aircraft leaves the construction site of an Ebola treatment center in Tubmanburg, Liberia, on October 15, 2014.

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Aid workers from the Liberian Medical Renaissance League stage an Ebola awareness event October 15, 2014, in Monrovia. The group performs street dramas throughout Monrovia to educate the public on Ebola symptoms and how to handle people who are infected with the virus.

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Ebola survivors prepare to leave a Doctors Without Borders treatment center after recovering from the virus in Paynesville, Liberia, on October 12, 2014.

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A man dressed in protective clothing treats the front porch of a Dallas apartment on October 12, 2014. The apartment is home to one of the two nurses who were diagnosed with Ebola after treating Thomas Eric Duncan, a Liberian national who traveled to Dallas and later died from the virus.

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Photos:The Ebola epidemic

A woman crawls toward the body of her sister as a burial team takes her away for cremation October 10, 2014, in Monrovia. The sister had died from Ebola earlier in the morning while trying to walk to a treatment center, according to her relatives.

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A man digs a grave on October 7, 2014, outside an Ebola treatment center near Gbarnga, Liberia.

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A person peeks out from the Dallas apartment where Thomas Eric Duncan, the first person diagnosed with the Ebola virus in the United States, was staying on October 3, 2014.

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A girl cries as community activists approach her outside her Monrovia home on October 2, 2014, a day after her mother was taken to an Ebola ward.

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A health official uses a thermometer September 29, 2014, to screen a Ukrainian crew member on the deck of a cargo ship at the Apapa port in Lagos, Nigeria.

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Workers move a building into place as part of a new Ebola treatment center in Monrovia on September 28, 2014.

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Medics load an Ebola patient onto a plane at Sierra Leone's Freetown-Lungi International Airport on September 22, 2014.

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A few people are seen in Freetown during a three-day nationwide lockdown on September 21, 2014. In an attempt to curb the spread of the Ebola virus, people in Sierra Leone were told to stay in their homes.

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Supplies wait to be loaded onto an aircraft at New York's John F. Kennedy International Airport on September 20, 2014. It was the largest single shipment of aid to the Ebola zone to date, and it was coordinated by the Clinton Global Initiative and other U.S. aid organizations.

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A child stops on a Monrovia street September 12, 2014, to look at a man who is suspected of suffering from Ebola.

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After an Ebola case was confirmed in Senegal, people load cars with household items as they prepare to cross into Guinea from the border town of Diaobe, Senegal, on September 3, 2014.

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A health worker wearing a protective suit conducts an Ebola prevention drill at the port in Monrovia on August 29, 2014.

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A burial team from the Liberian Ministry of Health unloads bodies of Ebola victims onto a funeral pyre at a crematorium in Marshall, Liberia, on August 22, 2014.

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Dr. Kent Brantly leaves Emory University Hospital on August 21, 2014, after being declared no longer infectious from the Ebola virus. Brantly was one of two American missionaries brought to Emory for treatment of the deadly virus.

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An Ebola Task Force soldier beats a local resident while enforcing a quarantine on the West Point slum on August 20, 2014.

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Local residents gather around a very sick Saah Exco, 10, in a back alley of the West Point slum on August 19, 2014. The boy was one of the patients that was pulled out of a holding center for suspected Ebola patients after the facility was overrun and closed by a mob on August 16. A local clinic then refused to treat Saah, according to residents, because of the danger of infection. Although he was never tested for Ebola, Saah's mother and brother died in the holding center.

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Workers prepare the new Ebola treatment center on August 17, 2014.

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Liberian police depart after firing shots in the air while trying to protect an Ebola burial team in the West Point slum of Monrovia on August 16, 2014. A crowd of several hundred local residents reportedly drove away the burial team and their police escort. The mob then forced open an Ebola isolation ward and took patients out, saying the Ebola epidemic is a hoax.

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A health worker disinfects a corpse after a man died in a classroom being used as an Ebola isolation ward August 15, 2014, in Monrovia.

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Aid worker Nancy Writebol, wearing a protective suit, gets wheeled on a gurney into Emory University Hospital in Atlanta on August 5, 2014. A medical plane flew Writebol from Liberia to the United States after she and her colleague Dr. Kent Brantly were infected with the Ebola virus in the West African country.

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Members of Doctors Without Borders adjust tents in the isolation area in Kailahun on July 20, 2014.

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Boots dry in the Ebola treatment center in Kailahun on July 20, 2014.

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Dr. Jose Rovira of the World Health Organization takes a swab from a suspected Ebola victim in Pendembu, Sierra Leone, on July 18, 2014.

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Red Cross volunteers disinfect each other with chlorine after removing the body of an Ebola victim from a house in Pendembu on July 18, 2014.

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A scientist separates blood cells from plasma cells to isolate any Ebola RNA and test for the virus April 3, 2014, at the European Mobile Laboratory in Gueckedou, Guinea.

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Health specialists work March 31, 2014, at an isolation ward for patients at the facility in southern Guinea.

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Story highlights

Experts fear that Ebola will mutate and become spreadable via cough or sneeze

Ebola is an RNA virus, meaning every time it copies itself, it mutates

Most mutations mean nothing, but some could change the way the virus behaves

Today, the Ebola virus spreads only through direct contact with bodily fluids, such as blood and vomit. But some of the nation's top infectious disease experts worry that this deadly virus could mutate and be transmitted just by a cough or a sneeze.

"It's the single greatest concern I've ever had in my 40-year public health career," said Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota."I can't imagine anything in my career -- and this includes HIV -- that would be more devastating to the world than a respiratory transmissible Ebola virus."

The World Health Organization says its scientists are unaware of any virus that has dramatically changed its mode of transmission.

"For example, the H5N1 avian influenza virus... has probably circulated through many billions of birds for at least two decades. Its mode of transmission remains basically unchanged. Speculation that Ebola virus disease might mutate into a form that could easily spread among humans through the air is just that: speculation, unsubstantiated by any evidence."

Osterholm and other experts couldn't think of another virus that has made the transition from non-airborne to airborne in humans. They say the chances are relatively small that Ebola will make thatjump. But as the virus spreads, they warned, the likelihood increases.

Every time a new person gets Ebola, the virus gets another chance to mutate and develop new capabilities. Osterholm calls it "genetic roulette."

As of October 1, there have been more than 7,100 cases of Ebola, with 3,330 deaths, according to the World Health Organization, which has said the virus is spreading at a much faster rate than it was earlier in the outbreak.

Ebola is an RNA virus, which means every time it copies itself, it makes one or two mutations. Many of those mutations mean nothing, but some of them might be able to change the way the virus behaves inside the human body.

"Imagine every time you copy an essay, you change a word or two. Eventually, it's going to change the meaning of the essay," said Dr. C.J. Peters, one of the heroes featured in "The Hot Zone."

That book chronicles the 1989 outbreak of Ebola Reston, which was transmitted among monkeys by breathing. In 2012, Canadian researchers found that Ebola Zaire, which is involved in the current outbreak, was passed from pigs to monkeys in the air.

Dr. James Le Duc, the director of the Galveston National Laboratory at the University of Texas, said the problem is that no one is keeping track of the mutations happening across West Africa, so no one really knows what the virus has become.

One group of researchers looked at how Ebola changed over a short period of time in just one area in Sierra Leone early on in the outbreak, before it was spreading as fast as it is now. They found more than 300 genetic changes in the virus.

"It's frightening to look at how much this virus mutated within just three weeks," said Dr. Pardis Sabeti, an associate professor at Harvard and senior associate member of the Broad Institute, where the research was done.

Even without becoming airborne, the virus has overwhelmed efforts to stop it.